1. Field of the Invention
The invention relates to a linear drive comprising a rod-like rotationally locked output drive part guided for axial movement in relation to a housing using a bearing means cooperating with its outer periphery, said bearing means being provided in a bearing portion of said housing, at least one position preset element, extending to the side, being provided on the output drive part, such preset element being shifted on axial movement of the output drive part along a position preset space extending alongside the output drive part.
2. Description of the Prior Art
Linear drives of this type are predominantly utilized in assembly and handling operations and are disclosed for instance in the European patent publication 0 219 439 A1. In this known case an output drive part adapted to be driven by the action of fluid to perform a linear movement is provided, which in a bearing portion lying in the front section of a housing, is encircled by a bearing means and is therefore is guided for movement in the longitudinal direction with lateral support. In order to be able to position the output drive part in a predetermined axial position a laterally projecting position preset element is provided laterally projecting from the output drive part, which runs along a lead screw, which is arranged in a position preset space arranged adjacent to the output drive part. Moreover several sensors are arranged in the position preset space adapted to respond to the position preset element and which cooperate with a brake means associated with the lead screw. If during the axial movement of the output drive part the position preset element draws close to one of the sensors, the brake means will be operated by a brake signal so that the lead screw is locked against rotation and a further axial movement of the position preset element and of the output part connected with same will be prevented.
The section, projecting from the housing, of the output drive part is extremely frequently subjected to high transverse forces during operation. For instance the output drive part may be provided with a gripping means, which is to convey heavy loads. It is furthermore possible for further linear drives to be mounted in order to produce a multi-axial handling system. It is therefore necessary to guide the output drive part in relation to the housing along a relatively long bearing portion and to support it in the transverse direction. This leads to a correspondingly larger overall size of the housing.